package 开始的剑指offer8月.搜索与回溯算法;
// https://leetcode-cn.com/problems/ju-zhen-zhong-de-lu-jing-lcof/
public class 剑指Offer12矩阵中的路径0826 {
    class Solution {
        public boolean exist(char[][] board, String word) {
            char[] words = word.toCharArray();
            for(int i = 0; i < board.length; i++) {
                for(int j = 0; j < board[0].length; j++) {
                    if(dfs(board, words, i, j, 0)) return true;
                }
            }
            return false;
        }
        boolean dfs(char[][] board, char[] word, int i, int j, int k) {
            if(i >= board.length || i < 0 || j >= board[0].length || j < 0 || board[i][j] != word[k]) return false;
            if(k == word.length - 1) return true;
            board[i][j] = '\0';
            boolean res = dfs(board, word, i + 1, j, k + 1) || dfs(board, word, i - 1, j, k + 1) ||
                    dfs(board, word, i, j + 1, k + 1) || dfs(board, word, i , j - 1, k + 1);
            board[i][j] = word[k];
            return res;
        }
    }

}
